Its coordinates are 20&deg56'8" N and 107&deg3'18" E in DMS (Degrees Minutes Seconds) or 20.9356 and 107.055 (in decimal degrees). Its UTM position is YJ11 and its Joint Operation Graphics reference is NF48-16.

Current local time is 07:08; the sun rises at 08:08 and sets at 20:15 local time (Asia/Phnom_Penh UTC/GMT+7). The standard time zone for Baie d' Halong is UTC/GMT+7
In 2015 DST starts on - and ends on -.

A Bay is a coastal indentation between two capes or headlands, larger than a cove but smaller than a gulf.